[PowerPC] Make new auxv format default

Assume ELF images without OSREL use the new auxv format.

This is specially important for rtld, that is not tagged. Using
direct exec mode with new (ELFv2) binaries that expect the new auxv
format would result in crashes otherwise.

Unfortunately, this may break direct exec'ing old binaries,
but it seems better to correctly support new binaries by default,
considering the transition to ELFv2 happened quite some time
ago. If needed, a sysctl may be added to allow old auxv format to
be used when OSREL is not found.

Reviewed by:	bdragon
Sponsored by:	Eldorado Research Institute (eldorado.org.br)
Differential Revision:	https://reviews.freebsd.org/D25651
This commit is contained in:
Leandro Lupori 2020-08-24 13:40:35 +00:00
parent 2b9f12f6b2
commit fb27a570ad

View File

@ -36,7 +36,22 @@ __elfN(powerpc_copyout_auxargs)(struct image_params *imgp, uintptr_t base)
Elf_Auxinfo *argarray, *pos;
int error;
if (imgp->proc->p_osrel >= P_OSREL_POWERPC_NEW_AUX_ARGS)
/*
* XXX If we can't find image's OSREL, assume it uses the new auxv
* format.
*
* This is specially important for rtld, that is not tagged. Using
* direct exec mode with new (ELFv2) binaries that expect the new auxv
* format would result in crashes otherwise.
*
* Unfortunately, this may break direct exec'ing old binaries,
* but it seems better to correctly support new binaries by default,
* considering the transition to ELFv2 happened quite some time
* ago. If needed, a sysctl may be added to allow old auxv format to
* be used when OSREL is not found.
*/
if (imgp->proc->p_osrel >= P_OSREL_POWERPC_NEW_AUX_ARGS ||
imgp->proc->p_osrel == 0)
return (__elfN(freebsd_copyout_auxargs)(imgp, base));
args = (Elf_Auxargs *)imgp->auxargs;